Grading before construction establishes both the shape of the land and how water will move across it once a house is built — two things that are much easier to get right before construction than after.
The grading process
Grading typically starts with rough grading — cutting and filling to get the site roughly to its intended shape — followed by finish grading once major construction is complete, which fine-tunes the surface for landscaping and final drainage. Ahead of home construction, the priority is establishing a stable, correctly sloped building pad and ensuring water moves away from the future foundation in every direction.
Why this happens before the foundation, not after
Grading decisions made before construction are far cheaper to adjust than fixing drainage problems around a finished home. Once the house, landscaping and hardscaping are in place, correcting a grading mistake often means tearing out and redoing work that's already finished.
See our Grading and Building Pad pages for how these two phases work together.